America is coming apart, warns Robert Putnam. It’s all due to a growing lack of social connection, and it’s visible in our relationships, communities, and deeply riven politics.

The bottom line is that we just don’t trust each other anymore, he said. But there are places to start.

The Peter and Isabel Malkin Professor of Public Policy, Emeritus and author of the influential 1995 book “Bowling Alone” spoke at a John F. Kennedy Forum in a March 12 conversation with former Kennedy School Dean David Ellwood, the Isabelle and Scott Black Professor of Political Economy, Emeritus. 

Putnam began with a discussion of national politics. He noted that President Trump’s critics blame him for our problems.

“America is in deep trouble,” said the 84-year-old political scientist. But Trump, he explained, didn’t create the turmoil. “He’s a symptom.”

“The real threat of what’s happening right now in America is not what’s on the surface, but the fact that the underlying causes of that are still there,” said Putnam. “And they will still be there when Trump is long gone unless we do something about it.”

That, said Putnam, is because our isolation — our lack of social capital — is growing worse, particularly among people with less education. “What the election showed is that the people, and above all the working class in America, were isolated. That’s why Trump won,” he said.

Putnam spoke a bit about his latest book, “The Upswing,” co-authored with his former student Shaylyn Romney Garrett. He drilled down on the data about what he called “political polarization, economic inequality, social isolation, and cultural self-centeredness.”

Putnam showed a series of graphs, all of which described a rough bell curve, starting low, peaking, and then coming back down. All of them, he explained, covered the period from roughly 1890 to 2020 in the U.S.

The first measured “political comity or bipartisanship,” which hit its high during the presidency of Dwight D. Eisenhower, “the most bipartisan — or nonpartisan — president in our history.” While that chart continued its high through John F. Kennedy’s presidency, its decline has been steady since.

“Now is probably the most politically polarized period in American history, with the exception of a period between 1860 and 1865.” He paused to make sure the room understood why he chose those dates. “That’s how close we are to a civil war,” he said.

The next chart, with a very similar curve, graphed economic equality, which has once again reached such a low level that it rivals the 1890s Gilded Age. A graph of social cohesion followed that same curve.

“Americans were very socially isolated at the beginning of the 20th century.” During that period of industrialization and urbanization, he said, “Large numbers of people were moving from villages in Sicily or villages in Iowa to the big city,” leaving their families and community connections behind. “And they had not yet made new ones.”

But they would.

“You see coming out of the ’30s and up until the ’60s, Americas were becoming much more trusting of one another,” he said.

Describing his own college experience in the ’60s, he recalled, “Most Americans trusted one another. Seventy-five, maybe 80 percent of Americans said they trusted other people,” Putnam said. “I think the latest number I saw was 10 percent of Americans say they trusted other people. And it’s still going down. We’ve still not stopped declining in our sense of connection with one another.”

The roots of these declines have many causes. The first is our definition of community — who is the “we” that makes up America. “The ‘we’ that we built over the course of the first two-thirds of the 20th century was a shriveled ‘we,’” said Putnam. “It was not just a white male ‘we,’ but it was more white than nonwhite” as well as more male than female.

“If we have a new progressive era, it has to have a more capacious sense of ‘we,’” he said.

We are also now isolated by social class, with the biggest gap being between those with college educations and those without. “The people who are left behind are the non-college-educated part of America.

“Only one-third of America has a college degree,” he said. “Do the math. We are never going to win unless we can begin to connect with the less-educated parts of America.”

Framing the issue as not an economic issue but a moral one, Putnam brought up Hillary Clinton’s ill-phrased dismissal of the “deplorables” who supported Trump.

“It’s not just about economics. Two-thirds of American society are not just unhappy about the fact that they don’t have good income or great chances of upward mobility. They don’t think we respect them — and we don’t,” Putnam said, referring to the college-educated, mostly middle-class or higher professional, corporate, and managerial class.

What we have to do is connect, he advised. Rebuild those social networks that allowed Americans to interact across class and education lines. And while many tout in-person connections, Putnam said, “It’s a mistake to think we have to have either face-to-face or virtual connections. Most of our connections are alloys, partially face-to-face and partly virtual.”

Such connections can help us bond in ways not connected with politics. He then gave a very local example: “I happen to be a Red Sox fan,” he said. “If you want to build connections among people from different parts of Boston or different age groups or different genders, bond in Fenway Park.

“Bridging in one direction, often depends on bonding in some other dimension,” he noted.

Ultimately, he said, “It is absolutely crucial that this new movement be based on youth. There are cultural things that young people of any class can bond on, like memes, and bridge other directions.

“I’m not giving you an answer,” he said. “I’m giving you a strategy for approaching an answer.”